Slide valve for steam engines



1955 c. GARBE 2,766,734

SLIDE VALVE FOR STEAM ENGINES Filed March 15, 1954 ID A B i2 A G E G 26 F F 26 E K 1/6 a a K "W "H 7 y i IN VEN TOR. CURT GARBE ATTORNEY I United States SLIDE VALVE FOR STEAM ENGINES Curt Garbe, Berlin-Lichtenberg, Germany Application March 15, 1954, Serial No. 416,331

4 Claims. (Cl. 121-133) This invention relates to valve arrangements, and more particularly to slide valves for controlling the operation of a cylinder of a steam engine.

An object of the invention is to provide a slide valve, especially for use in locomotives, which, in addition to its control of the operation of the cylinder under load, causes automatically through its own conduits and through its direct communications with the cylinder of the locomotive a pressure equalization between the two opposite ends of said cylinder during an idle running of the locomotive, so that the hitherto customary pressure equalization including the smoke box of a locomotive in its circuit and, as a result, an early wear and tear of the sliding elements of the slide valve and in the cylinder of the locomotive by particles sucked from the smoke box are eliminated.

Another object of the invention is to improve on the construction of slide valves, especially of the piston type, as now customarily made.

Other objects and structural details of the invention will be apparent from the following description when read in conjunction with the accompanying drawings forming part of the specification, wherein:

Fig. l is a sectional view of a slide valve according to the invention, said figure illustrating the elements of the slide valve in a position during operation of the steam engine or locomotive under load, and

Fig. 2 is a sectional view of the slide valve shown in Fig. 1, wherein, however, the elements of the slide valve are in a different position during an idle running of the steam engine or locomotive.

Referring now to the drawings, generally indicates a slide valve or piston valve according to the invention, which controls the operation of a piston 12 in a cylinder 14 of a locomotive. The slide valve 10 comprises a reciprocable rod 16 carrying a pair of spaced piston-like elements E. Each element E including a sleeve-like portion 18 abutting against a coller 20 of the rod 16 is tightly held in its position on the rod 16 by means of nuts 22 screwed on threaded portions of the rod 16. Furthermore, each element or piston E has an annular sealing surface 24 at its inner end surface and carries a pair of piston rings A at its circumference.

A cylindrical body F is slidably mounted on each sleeve 18 of each element E. A spring G arranged in a cavity 26 of the body F and engaged at its ends with said body F and with the element E tends to urge the body F against the collar 20 into the position shown in Fig. 2. Each body F has an annular sealing surface 28 at its outer end surface for cooperation with the annular sealing surface 24 of the element B when the body F is in the position shown in Fig. 1. Furthermore, each body F has a plurality of passages K extending in the direction of the longitudinal axis of said body F. Moreover, each body F carries a pair of piston rings B at its circumference.

The piston rings A and B of the members E and F respectively are in sealing engagement with the wall of the "ice bore 32 of the valve casing 34 receiving the above described elements of the slide valve.

The above described slide valve or piston valve controls the ports H and J of the cylinder 14 of the steam engine.

Steam may enter the interior of the slide valve 10 through the inlet 36 which is controlled by a control valve (not shown) in a manner known per se.

The rod 16 of the slide valve 10 is reciprocated by a controlling mechanism known per se (not shown).

The annular surface of the body F subjected to the action of fresh steam supplied through the inlet 36 is of such a size that a tight engagement of the component parts E and F with each other is assured even if the supply of steam is throttled to a great extent. The springs G exert such a force that, even at the highest speed during an idle running, the displaceable bodies F are tightly held against the collar 20 in the position shown in Fig. 2 in spite of the forces of the reciprocating masses; thus undesired knocking eifects are avoided.

The lubrication takes place by lubricating sockets in a manner known per se in the art of regulating slide valves. The sliding surfaces have sufficient clearance; they are provided with labyrinth packings and resilient piston rings as customary for example in the so-called Schulz-slide.

The operation of the slide or piston valve according to the invention is as follows:

When upon opening of the control valve (not shown) steam enters into the interior of the valve casing 34 through the inlet 36, the steam urges the displaceable bodies F against the elements E against the action of the springs G into the position shown in Fig. 1. Thus, the sealing surfaces 24 and 28 of the elements E and bodies F are in tight engagement with each other. On each side of the slide valve 10 the combined and tightly engaged element E and body F control the associated port H or .l respectively during controlled reciprocating movements of the rod 16.

Now, when for an idle running of the locomotive the steam is shut off by closing the control valve controlling the inlet 36, the springs G displace the bodies F relative to the elements E into the position shown in Fig. 2. Now the pressure equalization between the two opposite ends of the cylinder 14 may take place, for example in the direction of the arrows Z (Fig. 2), through the ports H and J and the interior of the valve casing 34 containing the mechanism of the slide or piston valve 10.

I have described a preferred embodiment of my invention, but it is understood that this disclosure is for the purpose of illustration, and that various omissions and changes in shape, proportion and arrangement of parts, as well as the substitution of equivalent elements for the arrangements shown and described may be made without departing from the spirit and scope of the invention set forth in the appended claims.

What I claim is:

l. A slide valve for steam engines, comprising in combination: a valve casing having a longitudinal bore and a pair of spaced ports for connecting said bore with opposite ends of a cylinder, a reciprocable rod arranged in the bore of said valve casing coaxially therewith, a pair of controlling means mounted on said rod for cooperation with said ports so as to control same, each controlling means including a first member and a second member movable relative to each other, the second members of said pairs of members being arranged adjacent to each other, one of said two members of each pair of members being fixed on said rod, limiting means arranged for cooperation with the movable members of said pairs of members, and resilient means interposed between the members of each pair of members for spreading same apart and urging the movable member of each pair of members against said limiting means, the first and second members of each pair of members being capable of tight engagement with each other at their sides facing each other upon action of steam on the movable members against the action of said resilient means, and each of said second members having at least one passage leading from the side facing its associated first member to the side facing the second member of the other pair of members so that a communication between said ports through said passages and the interior of the valve casing may be established for pressure equalization between the ends of the cylinder when during an idle running of the steam engine the resilient means urge the members of each pair of members into a spread position.

2. In a slide valve as claimed in claim 1, the first member of each pair of members being fixed to the rod.

3. In a slide valve as claimed in claim 1, the sides of the first member and second member facing each other in each pair of members including sealing surfaces for mutual cooperation.

4. In a slide valve as claimed in claim 1, the first member of each pair of members being in the shape of a piston having a center sleeve engaged with said rod, said limiting means being secured to said rod, clamping means engaged with said first member for urging its sleeve into abutting engagement with said limiting means, and said second member being slidable on said sleeve of said first member and being capable of engagement with said limiting means under the spreading action of said resilient means.

References Cited in the file of this patent UNITED STATES PATENTS 1,647,931 Petty Nov. 1, 1927 1,675,320 Allzeit July 3, 1928 1,950,705 Trofimofi Mar. 13, 1934 FOREIGN PATENTS 350,808 Great Britain June 18, 1931"' 

